1. Field of the Invention
The present invention relates to a dicing machine for cutting a CSP plate into pellets and transferring and putting them in a transport tray.
2. Related Arts
Referring to FIG. 12, a chip size package (abbreviated as xe2x80x9cCSPxe2x80x9d) plate 100 has a plurality of semiconductor chips hermetically packaged with glass, epoxy resin or such like, and it can be cut crosswise along the crossing lines 101 and 102 into separate pellets or CSPs. The so separated pellets are put in a transport tray to be shipped or transported to a selected assembling line in the electronic device manufacturing factory.
Referring to FIG. 13, a CSP plate 100 is attached to a holder frame F with an adhesive tape T, and the CSP plate-and-holder frame is brought to the dicing station in which the CSP plate is cut into squares. Such adhesive tapes are thrown away after being used. Lots of such disposable tapes when thrown away will cause significant contamination in the surroundings, and the throwing-away of such disposable tapes is disadvantageous from the economical point of view. Referring to FIG. 14, a reusable jig holder 103 may be used to hold a CSP plate 100 thereon in place of such a disposable tape. The CSP plate 100 can be fixedly held on the reusable jig holder 103 by applying negative pressure to its longitudinal opposite sides as later described. Likewise, the jig holder 103, in its turn, is sucked on the working table of dicing machine to cut the overlying CSP plate while being washed with water to remove pieces of debris from the diced CSP plate.
As seen from FIG. 14, the jig holder 103 has crosswise grooves 104 and 105 made in alignment with the crosswise cutting lines 101 and 102 of the CSP plate 100. These grooves 104 and 105 allows the cutter blade to enter freely after cutting the overlying CSP plate. Each square section defined by the crosswise grooves 104 and 105 has a single first suction hole 106 at its center and two second suction holes 107 on its diagonal line. Each first suction hole 106 passes through the full thickness of the plate from its front to back surface whereas each second suction hole 107 communicates with the engagement holes 108, 109 and 110, which are made in the opposite longitudinal sides of the plate 100 for applying negative pressure to the overlying CSP plate while being transported. The overlying CSP plate 100 is fixedly held to the jig holder 103 by applying negative pressure through the first suction holes 106 from the working table while being diced.
While the CSP plate 100 is being cut, minute pieces of debris are mixed in the washing water, and then the contaminated water is drawn through the crosswise grooves. The contaminated water is apt to invade into the space between the rear side of each pellet P and the underlying jig frame 103 to leave some minute pieces of debris there, thus allowing some pellets to be contaminated with such minute pieces of debris.
After washing the diced CSP plate, all minute pieces of debris can be washed away from the top surface of each pellet P, but the minute pieces of debris cannot be removed from the rear side of the pellet P.
As a result, contaminated pellets can be transported to the assembling line in the factory. The same problem will be caused in case of diced CSP plate attached to their frames with adhesive tapes T (FIG. 13); contaminated water is allowed to invade into the pellet-to-frame gap through the cutting slots. There has been, therefore, an increasing demand for removing minute pieces of debris from the rear side of each and every pellet before putting it in the transport tray.
One object of the present invention is to provide a dicing machine which is capable of removing minute pieces of debris from the rear side of each and every pellet before putting in a transport tray.
To attain this object, a dicing machine for cutting a CSP plate into pellets to put them in a transport tray including a CSP plate bearing table on which a diced CSP plate is to be laid, a transport tray station in which a transport tray is laid to receive individual pellets, and pick up-and-transport means for picking a selected pellet from a diced CSP plate and for putting the so selected pellet in an allotted place in the transport tray, is so designed according to the present invention that it further includes cleaning means for wiping and removing minute pieces of debris if any from the rear side of each pellet on the way from the CSP table bearing table to the transport tray station.
The pick up-and-transport means may comprise movable pellet-suction means for carrying a selected pellet and an elongated guide for guiding the movable pellet-suction means while it travels on the way from the CSP plate bearing table to the transport tray station, thereby allowing the cleaning means to wipe and remove minute pieces of debris if any from the rear side of each pellet.
The cleaning means may comprise a wiper for removing minute pieces of debris if any from the rear side of each pellet, washing liquid supply means for supplying the wiper with the washing liquid, and a drain for draining used washing liquid.
The wiper may comprise a rotary sponge roll, which has the washing liquid supply means fitted in the center of the sponge roll.
Minute pieces of debris can be removed from the rear side of each and every pellet while being transported to the transport tray station, and therefore no extra time is required for cleaning.
Other objects and advantages of the present invention will be understood from the following description of a dicing machine according to one preferred embodiment of the present invention, which is shown in accompanying drawings.